1. Field of the Invention
The present invention relates to a photo filmstrip and a side printing method for the same. More particularly, the present invention relates to a photo filmstrip and a side printing method for the same, in which results of a side printing operation can be inspected with convenience.
2. Description Related to the Prior Art
A photo filmstrip includes a series of bar codes or patterned codes recorded in one of its side portions. The photo filmstrip also includes a series of information signs, such as a manufacturer sign, a photo film type (photo film speed), a type sign, and the like. Those codes and signs are all recorded photographically in forms of latent images in a line for manufacturing the photo filmstrip. When the photo filmstrip is developed in a photo laboratory for the purpose of photofinishing, the codes and signs appear in forms of visible images. The bar codes or the patterned codes are read by a bar code reader incorporated in a photographic printer, in order to designate printing frame numbers and determine a printing condition.
If the bar codes or the patterned codes are erroneously read, the user and the photofinishing agent are involved with troubles. It is important to form the bar codes or the patterned codes under an exposing condition, i.e., light intensity suitable for the photo film speed, so that they have sufficient optical density after being developed. The photo filmstrip as produced is transferred to a subsequent line. In the course of transferring of the photo filmstrip, a predetermined number of samples of the photo filmstrip are separated from strips produced in each the lots of the line, and are transferred to an inspecting line. In the inspecting line, those samples of the photo filmstrip are developed, to visibilize the bar codes or the patterned codes. Then optical density of at least one of the bar codes or the patterned codes is measured, and evaluated to check acceptability of the exposing condition.
A single bar included in the bar codes or the patterned codes is defined to have only a width of 0.455.+-.0.075 mm, and thus have a considerably small area. It is excessively difficult to measure the density of a single bar with stability, because the measurement is influenced by low density of unexposed portions around each single bar.